lunduniversity | Researchers have long been aware that endogenous retroviruses
constitute around five per cent of our DNA. For many years, they were
considered junk DNA of no real use, a side-effect of our evolutionary
journey.
In the current study, Johan Jakobsson and his colleagues
show that retroviruses seem to play a central role in the basic
functions of the brain, more specifically in the regulation of which
genes are to be expressed, and when. The findings indicate that, over
the course of evolution, the viruses took an increasingly firm hold on
the steering wheel in our cellular machinery. The reason the viruses are
activated specifically in the brain is probably due to the fact that
tumours cannot form in nerve cells, unlike in other tissues.
“We
have been able to observe that these viruses are activated specifically
in the brain cells and have an important regulatory role. We believe
that the role of retroviruses can contribute to explaining why brain
cells in particular are so dynamic and multifaceted in their function.
It may also be the case that the viruses’ more or less complex functions
in various species can help us to understand why we are so different”,
says Johan Jakobsson, head of the research team for molecular
neurogenetics at Lund University.
The article, based on studies of
neural stem cells, shows that these cells use a particular molecular
mechanism to control the activation processes of the retroviruses. The
findings provide us with a complex insight into the innermost workings
of the most basal functions of the nerve cells. At the same time, the
results open up potential for new research paths concerning brain
diseases linked to genetic factors.
“I believe that this can lead
to new, exciting studies on the diseases of the brain. Currently, when
we look for genetic factors linked to various diseases, we usually look
for the genes we are familiar with, which make up a mere two per cent of
the genome. Now we are opening up the possibility of looking at a much
larger part of the genetic material which was previously considered
unimportant. The image of the brain becomes more complex, but the area
in which to search for errors linked to diseases with a genetic
component, such as neurodegenerative diseases, psychiatric illness and
brain tumours, also increases”.